Container having frangible opening means

ABSTRACT

A container (4) has a closure (15) which consists of a flange (6) and a lid (1) which are joined together all the way round by a failure zone (2). When the container is originally sealed the closure is inserted into the opening and the flange is fixed to a flanged top surface (5) of the container which surrounds the opening. The failure zone is located at the point at which the internal surface (3) of the opening meets the top surface of the opening. The lid is dished inwards within the failure zone in such a way that the outer edge of the dishing (7) forms a guide (10) with the internal surface (3). A surface (8) of the lid extending parallel with the top surface is connected to the guide (10). The lid is broken open and is torn along the length of the failure zone by a locally applied force. The application of force inwards will as a rule move the lid over the distance a until the surface (8) makes contact with a ledge (11) located inside the container (4). The surface (8) supporting the material of the lid thus forces the guide (10) against the wall of the container and holds the lid in a sealing position inside the opening. The lid adopts a similar position in a re-sealed container. Gripping devices, preferably in the form of stiffening ribs, make it easier to remove the lid from the position just mentioned.

This is a continuation of application Ser. No. 210,896, filed, Nov. 28,1980; now U.S. Pat. No. 4,332,332.

FIELD OF THE INVENTION

The present invention relates to a container with an opening facingupwards in the top surface, said container being provided with a closurefor the opening, said closure consisting of a fastener and a lid whichare joined together all the way round by means of a failure zone, saidclosure being inserted into the opening and forming a seal with thecontainer. By means of a locally applied force, preferably a compressiveforce, the lid may be torn open along the failure zone and may be causedto move inwards by means of a force directed towards the inside of thecontainer to a point at which, having moved over the distance "a", thelid will, on the one hand, make contact with a surface running parallelwith the top surface, and will on the other hand, take up a positionwhich will make any further opening difficult. The lid has a grippingdevice for the removal of the lid from the position just mentioned whenopening the container.

BACKGROUND

We are already familiar with a closure for a container of the typeindicated above from U.S. Pat. No. 3,998,354. This closure has certaindisadvantages and is also not suitable for use with containers which aremanufactured and filled in large numbers for the following reasons:

1. The internal width of the mouth of the container is greatlyrestricted by the fastener of the closure. The removal of the contentsis made much more difficult, particularly where the diameter of themouth is small.

2. Although admittedly the known closure is individually formed by aninjection moulding process, it does have a complicated shape. Itsmanufacture is consequently expensive and relatively time-consuming.From the mechanical point of view this closure is best suited for usewith small openings in metal containers. The attachment to the body ofthe container is unreliable where the container mouth is large, with theassociated risk that the closure will be several times more expensivethan the actual body of the container.

3. The known closure is not stackable. It is not capable of beinghandled in a practical manner during transport or storage. Nor is itpossible to feed such closures in a practical manner to a device forclosing the container.

4. The known gripping device is not located in a practical manner, sinceit extends over the failure zone. This prevents the use of welding orsimilar fastening methods.

5. The use of the edge of the failure zone in the lid for snapping-in incombination with compression is functionally unsatisfactory, since theedge of the failure zone will vary from one container to another. Dirtmay also collect between the edge of the failure zone and the supportingflange. No reference is made in the Patent to trouble-free snapping-in.

6. There are two areas in the closure where sealing may be poor, one ofthese being where the closure is introduced into the opening, and theother between the fastener and the lid after it has been separated fromthe failure zone. Poor sealing is likely to be greater at the firstpoint than at the second.

7. There is a risk of the fastener part of the closure falling from themouth of the container as it is opened, especially in the case of largeopenings.

8. In the case of both injection moulded and blow moulded containers, itis difficult to achieve a satisfactory fit between the container and theclosure. Only special plastic materials, e.g. polyethylene, exhibitsufficient elasticity to be capable of snapping-in in the manner shownin FIG. 4 of the patent. Where the internal pressure is the same, thewall strength of the container must be high irrespective of whether itis made of metal or of a plastic material. The body of the containermust always possess sufficient strength to allow the necessary reductionto take place in the dimensions of the fastener when it is attached tothe container.

9. An elastic plastic material such as polyethylene can easily be thecause of poor sealing, since such plastic materials change with timebecause they always flow a little.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a container with aclosure of the type described in the Field of the Invention in which theindicated disadvantages are avoided and which is able to satisfy therequirements of large-scale production. The container and the closureare also designed to fit together in such a way as to be stackable bothindividually and when full, and additionally they are capable of beingmanufactured at a reasonable cost. Furthermore, they are easilyassembled and provide a good seal.

This is achieved by positioning the failure zone in the lid at the pointat which the internal surface of the mouth of the container meets theactual top surface, whereby a flange located on the container is bondedto the fastener part of the closure, preferably by ultrasonic welding,and by causing the lid within the failure zone on the one hand, tosupport the gripping device with which the container is opened on theoutside, and on the other hand to be so dished inwards that the dishingforms a guide with the internal surface of the mouth, whereby a surfacerunning parallel with the top surface is connected to the guide, saidsurface after the lid has been torn open and if applicable after the lidhas moved inwards over the distance "a" making contact with a ledgelocated inside the container and forcing the guide against the wall ofthe container.

These characteristic features of the invention combine to produce theadvantage that the opening which receives the contents is particularlywide and is in no way obstructed by ledges or flanges which constrictthe opening. The contents are unable to contaminate corners difficult ofaccess, and there is no difficulty in seeing the contents once the lidhas been removed. The mating surfaces which hold the lid in place andwhich provide it with sealing and support are positioned so close toeach other and are designed to within such precise limits that thesnapping into place of the lid cannot be prevented by the mouth beingheavily contaminated with the contents. The connection between thecontainer and the closure is also found at the outermost circumferenceof the top surface, which makes it freely accessible to weldingapparatus.

A similar welded arrangement is described in U.S. Pat. No. 4,006,839.One disadvantage of this arrangement, however, is that the weld must beinterrupted to obtain loosening of the lid in the area of the grippingdevice when the container is opened. The interruption is made betweenthe edge of the container and the failure zone in an area where thegripping device extends outwardly and arranged for pulling. However, itis not possible to make this weld by means of a different weldingprocess so that it will be weaker, since no alternative welding processdoes in fact exist. The situation will arise in which either thecontainer is not properly sealed by the weld or the gripping devicebecomes detached because of a weld which provides a good seal but whichis also far too strong. Attempts to open the containers may produce asplit in that part of the lid which is intended to be used forre-sealing. A further disadvantage is that the failure zone does not runaround the mouth without interruption, but extends to the outer edge inthe area of the gripping device. It is also situated outside the actualedge of the mouth so that the lid which is intended to be torn off islarger than the mouth. This means that the container may not be openedby the application of external pressure to a central part of the closurecausing it to move inwards into the container in the direction of theaxis of the container. Feeding the lid into a welding apparatus callsfor care in its angular positioning with regard to the gripping deviceand the two dissimilar attachment zones.

In another embodiment of the present invention where the opening iscylindrical, provision is made for a number of radial stiffening ribswhich are uniformly distributed around the circumference to be locatedbetween the central parts of the top of the lid and an annular failurezone. The stiffening ribs are so designed as to serve both as a grippingdevice for opening the lid and as a stacking device for a pile of filledcontainers or of free closures. This measure provides considerablestiffening of the free lids which are to be used for re-sealing.

The lids seal better in this way and are stronger. The uniformdistribution of the stiffening ribs around the circumference has theadvantage that the pressing down of the failure zone no longer has tostart at a particular point on the circumference, but may be started atany one of these gripping devices. The same applies to the choice ofgripping device on subsequent opening of the container, where it is nolonger necessary for the container to be turned.

A further provision is that one individual gripping device chosen atrandom and adjacent to, for instance, a gripping surface which has beenmade rough by means of ribbing, bears operating instructions whichconsist, for example, of the text "1. PRESS" for starting to open thefailure zone and "2. PULL" for continuing the opening process inconjunction with the initial opening of the container and on anysubsequent opening in order to remove the contents. The correct mannerof using the closure is made clear to the user in this way, whereas thecontainers with which we are familiar and which lack instructions mayhardly be described as being suitable for their purposes. It is possiblein this way to prevent spilling of the contents.

A further provision is that the internal surface of the mouth of thecontainer which is essentially cylindrical at the top has a shape whichtapers inwards slightly and/or at the base at the point of transition tothe ledge forms a snap-in groove all the way round into which acorresponding projection or bead in the lid may be snapped. In this waythe sealing and retention of the lid is considerably improved by thesnap-in groove and the corresponding bead in the lid when it is used forre-sealing the container. Furthermore, the insertion of the lid when itis used for re-sealing is facilitated by the slightly conical guide.

In the case of containers with a circumference which is not circular, afunctional embodiment may be observed, for example, in the case of arectangular opening where the ledge with which the lid makes contact isin the form of indentations in at least two of the four lateral edges ofthe container. A section through one of the corners with a ledge in arectangular container will illustrate its similarity with a roundcontainer. The replacement of the lid will be facilitated if the wallsof the container are slightly inclined.

Finally, one embodiment of the lid exhibits an upward-facing raised areaalongside the dishing which forms the guide, said raised area beingconnected to the guide or to the dishing by means of radial ortangential ribs. In this way the local force required for opening thecontainer may be applied to the ribs. It is possible in the case of around lid with a raised area of the indicated shape within which theribs are located for the peripheral failure zone which is connected tothe outer extremities of the ribs to be broken open by force applied ina lateral direction or by force applied in the direction of the interiorof the container.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in greater detail in relation to anumber of figures of the annexed drawings, in which

FIGS. 1-4 are sectional views showing the stages of operation in openinga basic embodiment of the invention;

FIGS. 5-7 show an embodiment with radially located gripping devices;

FIG. 8 shows an embodiment with a combined gripping device and operatinginstructions;

FIG. 9 is a sectional view which shows an embodiment with a snap-ingroove;

FIG. 10 is a sectional view which shows an embodiment with differingtapers on the lid and on the surface of the opening;

FIGS. 11-12 show an embodiment with a rectangular opening, FIG. 11 beinga perspective view of the container and FIG. 12 a top plan view of thecontainer; and

FIGS. 13-17 show embodiments in which the lid has an upward-facingraised area at the center connected to the edges of the lid by means ofradial or tangential ribs.

DETAILED DESCRIPTION

FIGS. 1-4 show a section through part of the area of the edge of acontainer 4 at the mouth of the container. The wall 12 of the containerhas at its upper part an essentially cylindrical internal surface 3,which then becomes an outward-facing flange 5, which forms the extremityof the actual body of the container at its upper part. Extendingparallel to the top surface which is formed by the flange 5 is a ledge11 located at a certain distance down the wall of the container andjoined to the cylindrical internal surface 3.

The Figures also show a closure 15 composed of a lid 1 and combined withthe lid an external fastener 6 which extends all the way round. Thejunction between the lid and the fastener 6 is in the form of a failurezone 2. Located on the underside of the fastener is a welding projection19 which extends all the way round. The lid has a downward-facing dish 7which is joined to the fastener by means of essentially cylindrical lidcomponents 24, which, on the one hand, have an essentially cylindricalexternal surface or guide 10 corresponding to the cylindrical internalsurface 3 of the container, and on the other hand, have an essentiallyhorizontal annular surface 8 parallel with and facing the ledge 11.

FIG. 1 shows the enclosure 15 in the position adopted by the closurebefore it is attached to the body 4 of the container. In this positionthe welding projections 19 of the closure is in contact with the flange5 on the body of the container. The fastener and the flange are weldedtogether, to form a continuous annular seal, by exposure to, forinstance, ultrasonic sound whilst at the same time the fastener 6 of theclosure and the flange 5 are being held together under pressure.

FIG. 2 shows the position adopted by the closure after the weldingprocess described above has been completed. FIG. 2 also shows a distance"a" which is the distance between the annular surface 8 of the lid andthe ledge 11 inside the container.

FIG. 3 shows the position adopted by the lid 1 after an external forcehas been applied in a downward direction to the outermost edges of thelid, for instance to that part of the lid which is found attached to theannular surface 8. The downward force will break the joint between thelid and the fastener 6 in the failure zone 2, whereupon if forcecontinues to be applied in a downward direction the lid will be movedover the distance a so that its annular surface 8 will come into contactwith the ledge 11.

Once the lid 1 has been separated fully or partially from the fastener 6along its circumference, it is then raised in the manner shown in FIG. 4and the container is open. It may be seen from the Figure that thecontents in the opened container are accessible without difficulty, forinstance allowing portions to be removed separately, since there are nocomponents in the area of the mouth to obstruct the removal of thecontents.

To re-seal the container the lid 1 is replaced in the mouth of thecontainer, whereupon the guide 10 on the lid will operate in conjunctionwith the cylindrical internal surface 3 of the container to guide thelid into the position shown in FIG. 3. In so doing, that part of the lidwhich is connected to the annular surface 8 will cause the guide 10 ofthe lid to make reliable contact with the cylindrical surface 3, at thesame time that the annular surface 8 makes contact with the ledge 11.Reliable re-sealing of the container is thus made possible and any ofthe contents which may have become deposited on the ledge 11 will beable to flow back down into the actual container on re-sealing. Airtightre-sealing is also helped by the contact between the dishing 7 and theinternal surface of the container beneath the ledge 11. In theparticular case of containers designed to permit portions to be removedindividually, the dishing 7 is arranged in such a way that the jointbetween the dishing 7 and the annular surface 8 is located slightlyinside the wall of the container in order to ensure the unobstructedpassage of the contents from the ledge 11 into the actual container inconjuction with re-sealing. However, where a certain amount of thecontents still remain on the ledge 11, the guide 10 will ensure that therequired sealing between the lid and the container is provided when thecontainer is re-sealed.

It may also be seen from FIG. 2 that an originally sealed container ishermetically sealed, since the joint between the fastener 6 and theflange 5 prevents any passage to or from the inside of the container.Intact material is also to be found in the failure zone 2, with theresult that the sealing of the container is also guaranteed in thisarea.

FIGS. 5-7 show how the lid 1 in the closure 15 is provided with a numberof stiffening ribs 14 which are arranged radially at equal intervalsaround the circumference. The stiffening ribs are located between thecentral parts 13 of the top of the lid and the annular failure zone.FIG. 7 in particular shows how the stiffening ribs 14 may be used asgripping devices 9 for use when opening the container.

FIG. 6 shows how the stiffening ribs 14 have an upper edge 25 whichfaces outwards and downwards and which fits into the dishing 7 on thelid in such a way that the edge will serve as a stacking device when anumber of closures are piled one on top of the other. FIG. 6 also showshow the stiffening ribs 14 have an inwards and downwards facing edge 26which fits into the shape of the base of the container 4 in such a waythat the stiffening ribs 14 constitute a stacking device which providesstability and location when filled containers are piled one on top ofthe other.

FIG. 8 shows an embodiment in which the gripping device 9 is providedwith a gripping surface 16 which is made rough by means of ribbing andwhich bears operating instructions which consist, for example, of thetext "1. PRESS" for starting the opening and "2. PULL" for continuingthe opening of the container.

FIG. 9 shows how the lid is designed with a bead 18 and the container isdesigned with a snap-in groove 17. When the container is re-sealed, thehead 18 snaps into the groove 17 and improves the re-sealingcharacteristics.

FIG. 10 shows an embodiment in which the guide 10 of the lid 1 tapersmore than the internal surface 3. The shape of the lid before it isinserted into the mouth is shown in broken lines and the shape after ithas been inserted is shown in solid lines. In the case of a containerwhich has been re-sealed, this difference in taper places a certainamount of tension on those parts 24 of the lid which support the guidein order to improve the retention and sealing of the lid against themouth of the container after re-sealing. The elasticity of the materialalso causes the guide 10 to make contact with the cylindrical internalsurface 3 of the mouth over a large contact area after the container hasbeen re-sealed.

FIGS. 11-12 show an embodiment of the invention in which the opening atthe mouth is rectangular in form. The ledges 11 are in the form ofindentations 27 in at least two of the four lateral edges 23 of thecontainer. The stacking of both empty and filled containers on top ofeach other is facilitated by designing the walls of the container andthe indentations so that they are slightly conical in shape.

FIGS. 13-17 show embodiments in which the lid has an upward-facingraised area 20 alongside the dishing 7 which forms the guide 10. Theraised area is connected to the guide or the dishing by means of radialribs 21 or tangential ribs 22.

FIGS. 14a-b show details of a rib 21 and its function in conjunctionwith the opening of an originally sealed container. The solid lines inthe Figures show the position of the ribs at rest, whilst the brokenlines show the position of the ribs in their functional position. When aforce is applied as shown in FIG. 14b to the upper part of the rib(indicated by the arrow A), both the rib and the adjacent parts of thelid will be pressed downwards at the same time as the joint between thelid and the closure will be broken at the failure zone. Once the jointhas been broken, the rib 21 will form a gripping device for use inlifting the lid from the mouth of the container.

FIG. 16 shows how the application of horizontal force to a tangentialrib 22 will cause the rib and the adjacent parts 28 of the lid to movein the same direction of the failure zone of the closure at the sametime as other adjacent parts 29 will be caused to move away from thefailure zone, thereby causing the joint with the failure zone to bebroken. The two opposing arrows show how the force is applied, whilstthe third arrow B shows the direction in which the parts of the materialwill move away from the failure zone. It is also possible, of course, todesign an originally sealed container in such a way that it is brokenopen initially by the application of compressive force towards theinterior of the container in the manner which has already beendescribed.

FIG. 17 shows how the tangential ribs 22 are designed so as to fit theunderside of the dishing 7 when closures are stacked one on top of theother.

Provision is also made for a preferred embodiment incorporating all theabove embodiments in which the internal surface of the opening of thecontainer is slightly tapered towards the center. The correspondingparts of the lid are similar in form in this case.

The Figures also show the failure zone designed as a groove facinginwards from the upper surface of the closure. In an alternativeembodiment, the groove is similarly formed in the internal surface ofthe closure or in both the inner and outer surfaces of the closure.

The assumption is made in the above description, which consists only oftypical embodiments within the concept of invention, that the attachmentof the closure to the flange of the container is achieved by means ofwelding, and preferably by means of ultrasonic welding. It is clear thatsimilarly acceptable characteristics may be achieved in a container ifthe attachment of the closure to the container is made by other meanswhich will produce a joint of similar reliability. An example of such ajoint is the use of the process known as "hot melt".

The embodiments indicated and described above are typical applicationsof the concept of the invention. It is clear that other embodiments arealso possible within the scope of the invention.

What is claimed is:
 1. A container construction comprising a containerbody adapted for containing a product and including an annular wall andan annular flange extending outwardly from said wall at an upper edgethereof, said container body defining an open mouth within said wall,openable closure means closing said open mouth for sealing the productin said container body, said closure means comprising a lid including anannular wall engaged within the annular wall of said container body andan annular flange extending outwardly from said annular wall of the lidadjacent the annular flange of the container body, and sealing meansincluding a continuous, annular seal sealably and permanently connectingsaid annular flange of the container body with said annular flange ofthe lid to seal the product within the container body, said lidincluding an annular failure zone located radially inwards of saidsealing means in a position in which the failure zone can be ruptured byapplication of force to said lid to separate the flange of the lid fromthe remainder of the lid whereupon said flange of the lid remainssecured to the flange of the container body and said remainder of thelid is removable from the container body to gain access to the productin said container body, said remainder of the lid being thereafterinsertable into said container body to close the same by re-engaging theannular wall of the lid with the annular wall of the container body, thedisposition of said annular failure zone with respect to said sealingmeans and of said lid and container body being such that rupture of saidfailure zone is effected by relatively displacing said lid with respectto said container body whereafter said lid is removable from saidcontainer body by pulling said lid out of said body.
 2. A containerconstruction as claimed in claim 1 wherein said annular failure zonecomprises an annular notch in said lid at the juncture of said annularflange with the remainder of the lid.
 3. A container construction asclaimed in claim 2 wherein said notch is provided in the inner surfaceof said flange of the lid facing said flange of said body.
 4. Acontainer construction as claimed in claim 1 wherein said annularclosure and said annular failure zone are in surrounding relation andrupture of the failure zone is effected by displacing said lid inwardlyof said container.
 5. A container construction as claimed in claim 1comprising gripping means on said lid inwardly of said annular failurezone.
 6. A container construction as claimed in claim 5 wherein saidgripping means comprises ribs arranged on said lid to enable stacking ofa plurality of lids on one another.
 7. A container construction asclaimed in claim 6 wherein said ribs are also arranged to hold thebottom of a second container in secure supported position on said lid.8. A container construction as claimed in claim 7 wherein said ribs arearranged radially.
 9. A container construction as claimed in claim 7wherein said lid includes a central portion and said ribs extend fromsaid central portion to said annular wall of the lid.
 10. A containerconstruction as claimed in claim 9 wherein said central portion is anupwardly facing raised region.
 11. A container construction as claimedin claim 1 wherein one of said annular walls has a tapered surface fortightly engaging the other annular wall.
 12. A container construction asclaimed in claim 1 comprising snap engageable means on said annularwalls for holding the lid in engagement with the container body.
 13. Acontainer construction as claimed in claim 12 wherein said snapengageable means comprises a bead on one of said walls and a groove onthe other of said walls for receiving said bead.
 14. A containerconstruction as claimed in claim 13 wherein said bead and groove extendannularly.
 15. A container construction as claimed in claim 1 whereinsaid seal comprises an annular weld between the flange of the containerbody and the flange of the lid.
 16. A container construction as claimedin claim 1 wherein said annular walls are substantially cylindrical. 17.A container construction as claimed in claim 1 wherein said walls aredimensioned to provide a sealed relation when said lid is re-engagedwith said body.
 18. A container construction as claimed in claim 4comprising stop means for limiting the inward displacement of said lidwith respect to said container body.